Sylvania



R. E. HELLMUND.

METHOD OF AND APPARATUS FOR OPERATING INDUCTION MACHINES. APPLICATIONFILED OCT. 24. I9I6. RENEWED OCT. 12. 1920.

1,376,434. Patented May 3,1921.

4 SHEETS-SHEET I.

"I: 1 WITNESSES: INVENTOR R. E. HELLMUND.

METHOD OF AND APPARATUS FOR OPERATING INDUCTION MACHINES.

' APPLICATION FILED 001.24.1916. RENEWED OCT. 12. 1920.

37 434 Patented May 3, 1 921.

4 SHEETS-SHEET 2- wn EssEs: V v v INVEN1I'OR f2; 8, fiadolffl/fe//man ArR'N Y R. E. HELLMUND.

METHOD OF AND APPARATUS FOR OPERAHNG INDUCTION MACHINES.

APPLICATION FILED-OCT. 24.1916- RENEWYED OCT. 12, 1920.

1,376,434.. Patented 1... ,1921.

4 SHEETS-SHEET 3.

INVENTOR Pudm'fEHfl/mund.

fiat/(271. 'A'TTORNEY v R. E. HELLM'UND.

METHOD OF AND APPARATUS'FGR QPERAHNG INDUCTION MACHINES. APPLICATIONFILED ocT.A24'. 191s. RENEWED' ocT, 12. 1920. v

r 1,376,434. I Patenq'ed- May 3,1921

4 SHEETS-SHEET 4.

INVENTOR ATTORNEY UNITED STATES PATENT OFFIQE...

HOUSE ELEGTRIC AND MAN'UFACTURING COMPANY, A CORPORATION OF PENN- SYLVANIA.

METHOD OF AND APPARATUS "FOR OPERATING INDUCTION-MACHINES.

Specification of Letters Patent.

Patented May 3, 1921.

Application filed. October 24, 1916, Serial No. 127,380. Renewed October12, 1920. Serial No. 416,510.

To all whom it may concern:

Be it known that I, RUDoLr E. HELL .MUND, a subject of the Emperor ofGerprovement in Methods of and Apparatus i said auxiliary machine isthen transferred.

for Operating Induction -Machines, of which the following is aspecification.

My invention relates to a method of, and apparatus for, starting andregulating in duction machines, and it has for its object to provideapparatus of the character designated wherewith induction machines ofthe non-self-starting type may be simply, conveniently and effectivelystarted and brought up to any desired speed and whereby the startingmeans may then be employed for the regulation of the induction machinein improving the power-factor and speed regulation thereof.

In the accompanying drawing, Figure 1 is a diagrammatic view of aphase-converter of the well-known,single-phase, induction type, togetherwith suitable supply andcontrol circuits and attendant apparatusembodying a preferred form of my invention; Fig. 2 is a control diagramillustrating apparatus suitable for the control and operation of theswitches of the system of Fig. l in a preferred sequence; Fig. 3 is adiagrammatic view of an electromagnetic switch provided with a controlboardand suitable for use in the system of Fig. 1; Figs. 4-, 5, 7, 9, 11and 12 are diagrammatic views of modifications of the system shown inFig. 1; and Figs. 6, 8, and 10 are sequence charts illustrating apreferred order of switch operation in the systems of Figs. 5, 7 and 9,respectively. r

in copending applications, Serial Nos. 113,454. and 113,456, filed Aug.7, 1916, I describe and claim means whereby an aux: iliary commutatormachine is conductively associated with the primary winding of aphase-converter of the rotary induction type during the startingoperation and wherein to the secondary circuit of the phase-converterfor power --factor regulation and for similar exciting purposes.

The present system is in general similar to those Shown in-t heaforementioned-applh cations but the commutator machine is, at alltimes, connected to the secondary-or rotor circuit of the phaseconverter and, in this manner, more or less troublesome switchingoperations are avoided. At standstill, the phase-converter operatesmerely as a transformer in supplying energy to the auxiliary machine forstarting purposes, said energy obviously being supplied at full linefrequency- As the phase-converter comes up to normal speed, thefrequency of the current supplied to the auxiliary machine decreasesuntil it attains the normal slip frequency of the phase-converter. Bythen supplying a direct-current excitation to the auxiliary machine,direct-current excitation maybe supplied to the phase-converter forsynchronous operation and phase compensa tion, as is well understood.

For a more detailed understanding of my invention, attention is firstdirected to Fig. 1 in which a phase-converter of the singlephaseinduction type is'shown at 10, said machine comprising a phase-woundrotor 11, a primary stator winding 12 and a tertiary stator winding 13.Energy for the operation of the rotor is derived from any suitablesource, such, for example, as the secondary winding 14 of a transformer15, and energy derived directly from the secondary winding 14 iscombined with that derived from the tertiary winding 13 for theenergization of a polyphase system 16, as is well understood in the art.

The rotor 11 of the phase-converter 10 is provided with a phase-winding17 terminat ing in suitable slip rings 18 upon which bear brushescommunicating through suitable switches with an auxiliary commutatingmachine .20 mechanicallycoupled to the phaseconverter 10, as, forexample, by having its rotor member mounted on the same shaft therewith.The auxiliary machine 20 comprises a. rotor member 21, a main excitingfield winding 22, an auxiliary exciting field winding 23 and a cross orcompensating field winding 24.

Connection between the primary winding '12 of the phase-converter andthe source 13 is controlled by suitable switches 1 and '2. lwo phases ofthe rotor winding 17 may be connected in series with the armature, mainexciting and compensating field windings of the auxiliary machine by theclosure of suitable switches 6 and 9. The phases of the rotor windingsupplying energy to the machine may be changer by opening the switches Gand 9 and closing suitable switches 7 and 8 for a purpose to behereinafter more fully described. Direct-current excitation may besupplied for the auxiliary exciting field winding of the machine 20 froma suitable source by the closure of aswitch 5. The main exciting fieldwinding' 22 of the machine 20, together with a regulating resistor 2 maybe eliminated from the c' cuit by the closure 01"" 2 switch 3. Anadditional regulating resistor 27 may be eliminated from the supplycircuit oil? the machine 20 by the closure of a suitableshort-circuiting switch 4.

The switches l to 9, inclusive, may take any one of a variety of forms,the specific type employed constituting no part of the presentinvention. A suitable form is indicated in 3, being the well-knownelectro-magnetic switch provided with main contact embers and withauxiliary contact members coacting with a control b tor the energizationof interlocking circuits, as is well known in the art.

control segment 33: is adapte a plurality oi contact fingers idistinctpositions A, B, C and D and, so doing, to supply energy to the operatingcoils 1 to 9, inclusive, of the switches 1 to 9 from control battery 29,in accordance re ay 3() has its operating coil riser-ted in a lead thedriving motor 20 and controls the supply of energy to the operatingcoils oi"- switches 7 and 8, as will be here. more fully pointed out.

Having thus described 1 a system embody eration is as toll; 34 is f rstmoved poo switches l, 2. 6 and 9 a1 10 is connected to the sour e rotorof said machine being at the winding acts as the secondar i w T1 of anordinary tra sorm and S? p i energy to the auxiliai machine 90 th 0 theswitch 6, the resistor 26 being inc in circuit in order to prevent arush or c rent under the influence of the relat' high voltage developedat stand No.1 4 i sistor 27 is connected between the points 31 and 32 ofthe rotor winding 17 through the switch 9 and permits the circula on ofsecondary currents through a portion of the rotor winding. permittingthe building; up of torque within the rotor in nber 11. The passage ofcurrent to the di ving motor 2 draws up the core oft-he relay and prevents the closure of the switches 7 and 8 when the control segment 34 ismoved to the position B.

Usually, the rotor will be in such a position that a secondary voltagewill be induced between the points 32 and 33 of the rotor winding,sufiicing to start the machine 20. If, however, the rotor is atstandstill, in such position that insufficient electrometive force isroduced between the points 32 and 33 to start the machine, the relay deice 30 is unaffected, and the movement of the control segment 34: to theposition B closes the switches 7 and 8, connecting the driving motor 20to energized phases in toe rotor winding 17. Obviously, the passage ofcurrent to said driving motor instantly opens the contact members of therelay device 30 but, by shunting said contact mom-- bers with interlocks7-in and S-in, as shown, energy continues to be supplied to the motor20. Suitable interlocks 7-out and 8-out are placed in series with theoperating coils of the switches 6 and 9, respectively, so that saidswitches are not closed simultaneously with the switches 7 and 8.

The control segment 34 is maintained in the position B until the machine10 has been brought up to speed, whereupon said control segment is movedto the position C, closing the switches 3 and 4, thus eliminating theresistors 26 and 27 and the main exciting field winding 22 of themachine 20 from the circuit. There are thus produced two V-con nectedshirt-circuiting paths of low resistance for the rotor winding 17 of thephaseconverter 10, one of said paths traversing the switch and the othertraversing the coinpensating field winding 24- and the armature 21 ofthe auxiliary machine 20 and the switch 3. The machine 20 obviouslyperforms no function during this phase of the starting operation. whichmay be considered as a transition period. The control segment 34 isfinally moved to the position D. closing the switch 5 and establishingdirectcurrent excitation for the machi 20, which, thereupon suppliesdirect-exciting current to a portion of the rotor wiudii'igg 17,immediately increasing the rotor speed and causing the phase-converterto operate synchronously. thereafter mljiistiug the amount ofdirect-current excitation by any suitable means, such, for example, as aresistor 35, the power-factor of the phase converter 10 may be adjusted,as is well known.

Vhile I have thus sl'iown the auxiliac machine 20 employed normally as asour "1 of direct-current excitating current for power-factorcompensation, it is obvious that it may also be employed as a source ofdouble-frequency current for boosting or otherwise, as indicated in myaforemen' tioned applications, said other uses of the auxiliary machineconstituting no part of he present invention, the of which re you co y

sides in the cascade operation of the two machines during both thestarting and the op erating connections.

As an alternative to the structure shown in Figs. 1,2 and 3 for insuringthe derivation of starting current for the driving motor 20 from therotor 11, irrespective of the rest position of said rotor member I mayemploy the structure shown in Fig. l.

wherein the position of rest of the rotor member itself determines whatphase winding thereof is connectedte the motor 20. The phase-converterand starting motor are arranged as in the system of Fig. 1, and acontact segment 90, comprising two conducting, arc-shaped portions 91and 92,is mounted on the shaft otthe phase-converter and arranged tomake non-simultaneous contact with two sets of contact members or studs93 and 94C; Suitable connectionsare provided so that, if the rotormember comes to rest with the'member 90 in contact with the studs 93,the motor 20 is connected between the points 31 and 32 of the rotorwinding and the resistor 27 is connected between thepoints 32 and 33,whereas, if

the member 90 rests in contact with the studs 94, the motor 20 isconnected between the points 32 and 33. Thus, the motor 20 may bearranged to receive starting current at any position of the rotor whenat rest.

' l/Vhile I have thus shown two methods of insuring the supply of'lllltlfil startingcurrent to the driving motor under all condi-. tlons,it is obvious that varlous other ar- "ously, automatic means such asthose i: have illustrated are H1 generah to be preferred f to manualmeans.

I may associate a phasewonverter with a polyphase commutator startingmotor, as shown inF g. 5, and, by this means. obtain simple and;effective start with all posi- -tions of rest ot the phase-converterrotor.

A phaseconverter:10 similar to that shown in Fig. '1, ismechanicallycoupled to an auxiliary "polyphase'commutat r machine 36 comprisir anarmature 21 and combined induci. a \i wiud egwadapted to be energizedfrom a direc't currentsource 4-1 through an adjust ableeresistor forsynchronous operation ,of the phase-converter. The rotor 11 of thephase-converter 10'may be provided with a phase-converter and also tosupply a start- .the machine 36.

exciting tioid'windiugs 37. 38' and 39 together with an auxiliary fielding torque soon as rotation has commenced. g

The phase-converter 10 may be connected to the supply 1 throughswitches'l and 2. asbe'fore, and the field windings 37 and 39 of themachine 36 may be short-circuited by suitable switches and 43,respectively. The field winding 38 maybe eliminated by opening a switch45. The closure of a switch 46 closes a circuit across two of the phasewindings of the rotor 11.

The various switches are operated in the sequence indicated in Fig. 6 byany desired means; such for example, as a control system s milar to thatindicated in Fig. 1. At the out-set, the switches 1, 2 and 45 areclosed. energizing the primary winding of the phase-converter andpermitting current to flow instantaneously from the secondary or rotorwinding thereof through the switch 45 and the field winding 38 to therotor 21 of the machine 36., whence it divides, a portion passingthrough each of the other field windings and returning thence to therotor winding 17. The motor 36 thereupon starts and brings thephase-converter 10 up to the desired, speed. starting torque also beingprovided by the squirrel-cage winding 42. switches 13 and 44- are nextclosed deining the field windings 39 and 37 of the machine 36 by shortcircuiting. The field winding 38 is then deenergized by opening theswitch 415, and the switch 46 is simultaneously closed, whereuponcurrentsfrom the rotor winding 17 of the phase-converter are free tocirculate through a lowresistance path traversing the switch 46 orthrough a lowresistance path traversing the switches 43 and 44 and thearmature of Finally. the switch 47 is closed. providing directcurrentexcitation, as in thepreviously describedsystem.

.7 shows a system similarto those just described and suitable forapplication to a two-phase rotor winding and,-when taken in connectionwith the sequence chart ot Fig.'8. isseli explanatory. The essence ofthe operation is that, after the primary winding ofthe phase-converteris energized, current flows through all the field windings of theauxiliary machine, and the field windings 52 and 53 are then shortcircuited by the closure of suitable switches 43 and 4:9, preparatory tothe superposition of di met-cur entexcitation from the field \VlIKl-Ving 54; by the closure of a suitable switch 5"). Attention s directed tothe possibility retainingthcafield winding in circuit.

throughout the entire operation as commutating winding.

F 9 shows an alternative system for a quarter-phase wound rotorphase-converter, the said phases bemg independent and be-- ing connectedto four brushes in the auxilary start ng motor, The operatlon w ll beself-evident from Fig. 8, when taken in connection with Fig. 10 and theforegoing description.

In the system of Fig. 11, a phase-converter 10, of the same form asshown in Fig. 1, is associated with an auxiliary machine 70 of thepolyphase commutator type comprising an armature 71 and field windings72, 73 and 7 1. The armature 71 is provided with a commutator cylinderupon which bear brushes 75, 76 and 77 having a 120 space relation withrespect to each other. The axis of the field winding 72 liessubstantially midway between the brushes 75 and 76, and the axis of thewinding 74 lies substantially midway between the brushes 75 and 77 butthe axis of the field winding 73 is in substantially space quadraturewith the axis of the field winding 72.

At the outset, suitable switches 78 and 79 are closed so that the threebrush sets 75, 76 and 77 are connected together through a low-resistancepath. The outer termlnals of the field windings 72, 73 and 7-1 areconnected, respectively, to the terminals of the rotor winding 17 of themachine 10 and, therefore, the auxiliary machine 70. starts as arepulsion motor. At the very outset, the operation of the motor 7 O ispurely that of a single-phase machine but, as soon as the rotor 11 ofthe phase-converter begins to rotate, polyphase currents are supplied tothe machine 70 for subsequent operation as a polyphase commutatormachine. For the direct-current energization of the rotor' winding 17, Imay insert a distinct directcurrent exciting machine 81 in one of therotor leads.

The system of Fig. 12 is, in man respects, similar to that of Fig. 11except that the field windings 72, 73 and 74 are equally spaced fromeach other and each is mounted to operate partially as an exciting andpar tially as an inducing field winding. The brushes 75 and 76 may beconnected directly together through suitable switches 83 and 86, and theinner terminal of the winding 72 may be connected to the brush 75 by asuitable switch 85 and to the brush 76 by a suitable switch 84. Theswitch 86 serves to disconnect the brush 76 from the circuit. At theoutset, the switches 85 and 86 are closed. so that the auxiliary machine70 starts as a series-connected polyphase commutator machine, each fieldwinding being connected to its immediately adjacent brush. After thephase-converter has been brought up to speed, the switches 85 and 86 areopen and the switches 83 and 8a are closed, resulting in a reversal ofthe direction of phase rotation of the stator flux of the machine 70and, therefore, closing the same to operate as a generator and, bysuperposing suitable direct-current excitation thereupon,

the corresponding effect or effects may be produced in thephase-converter.

Instead of altering the connections of the field windings in the machineof Fig. 12, it is obvious that an equivalent result might be obtained byshifting the brushes thereof.

While, throughout this application, I have shown my system as applied tophaseconverters, it is obviously equally capable of application to alltypes of single-phase induction machines which require auxiliarystarting apparatus and subsequent regulating apparatus.

Attention is again directed to the fact that a starting mot-or employedin connection with the herein described invention is supplied withcurrent of line frequency only at the instant of starting, the frequencyof the current supply thereto falling off very rapidly as the mainmachine comes up to speed. Thus. the severe sparking conditionsattendant upon high frequency are encountered only for a very smallportion of the time.

VJhile I have shown my invention in a plurality of forms, it will beobvious to those skilled in the art that it is susceptible of variousminor changes and modifications with out departing from the spiritthereof and I desire, therefore, that only such limitations shall beplaced thereupon as are imposed by the prior art or as are set forth inthe appended claims.

I claim as my invention:

1. The combination with a source of single-phase alternating current, ofa dynamoelectric machine of the single-phase induction type having itsprimary winding connected thereto, a starting motor of the commutatortype for said machine mechanically coupled thereto and connected toderive its operating energy from the secondary winding thereof, andmeans for employing said starting motor as a regulating machine in thenormal operation of said induction machine.

2. The combination with a source of single-phase alternating current, ofa dynamoelectric machine of the singlephase induction type having itsprimary winding connected thereto, an auxiliary dynamo-electric machineof the commutator type mechanically coupled to said induction machine,and means for connecting said auxiliary machine to the secondary memberof said induction machine for operation as a starting motor.

3. The combination with a source of single-phase alternating current, ofa dynamoelectric machine of the single-phase induction type having itsprimary winding connected thereto, an auxiliary dynamo-electric machineof the commutator type mechanically coupled to said induction machine,means for connecting said auxiliary machine to the secondary member ofsaid induction machine for alternative operation as a starting motor, oras a regulating generator, and means for producing a unidirectionalfield in said auxiliary machine during generating operation, whereby acomponent of direct current is supplied thereby to said inductionmachine for synchronous operation.

4. The combination with a source of single-phase alternating current, ofa dynamoelectric machine of the single-phase induction type having itsprimary winding connected thereto, an auxiliary dynamo-electric machineof the commutator type mechanically coupled to said induction machine,and means for connecting said auxiliary machine to the secondary memberof said induction machine for alternative operation as a starting motoror as a regulating generator.

5. The combination with a dynamo-electric machine of the induction type,of an auxiliary dynamo-electric machine of the commutator type at alltimes electrically associated with the secondary member thereof, meansfor employing said auxiliary dynamo- I electric machine initially as astarting motor and subsequently as a regulating machine, and means forenergizing said auxiliary dynamo-electricmachine through said inductionmachine during the starting operation.

6. The combination with a phase converter of the induction type, of anauxiliary dynamo-electric machine mechanically couphase converter,whereby said auxiliary machine may, at times, be used as a startingmotor, a source of direct current and means for, at other times, somodifying said connections that said auxiliary machine is energized fromsaid direct-current source and caused to operate as a regulatingmachine.

7. The combination with a transformer comprising a single-phase primaryWinding and a plurality of movably mounted second ary windings arrangedto be successively inductively interlinked with said primary winding, ofa single-phase motor connected to normally derive electrical energy froma portion of said secondary windings and to move all of said secondarywindings, and means for automatically transferring the connections ofsaid motor to other of said secondary windings if the apparatus is atrest in such a position that the normal motor-energizing secondarywindings are not inductively interlinked with said primary winding.

8. The method of operating a phase-converter of the rotary inductiontype having its secondary member mechanically and electrically connectedto an auxiliary dynamoelectric machine which comprises initiallyoperating said auxiliary machine as a starting motor through saidphase-converter and the intervening connection and subsequentlyoperating said auxiliary machine as a regulating dynamo-electricmachine.

In testimony whereof, I have hereunto subscribed my name this 19th dayof Oct, 1916.

RUDOLF E. HELLMUND.

